1. Technical Field
The disclosure relates to a frequency detector for a reciprocating moving body, which detects a frequency of a motion waveform based on a motion trajectory of the reciprocating moving body that performs periodic reciprocating motion, and a swinging joint device that includes the frequency detector for the reciprocating moving body and varies rigidity of a joint.
2. Description of Related Art
For example, Japanese Patent Application Publication No. 2012-66375 (JP 2012-66375 A) discloses a robotic suit that appropriately assists walking of a user while a lower limb (from hip joint to toe) of the user is regarded as a moving body performing periodic reciprocating swinging motion. In the robotic suit, torque deviation between the robotic suit and the user is input such that the torque deviation is reduced by applying PID control (feedback control).
In addition, Japanese Patent Application Publication No. 2013-236741 (JP 2013-236741 A) discloses a one leg-type walking assist device which is attached to an affected leg of a user whose one leg is a healthy leg and the other leg is the affected leg, thereby assisting motion of the affected leg. The one leg-type walking assist device includes a waist attachment portion which is disposed on the side of the waist of the user, a femoral link portion which extends from the side of the hip joint to the side of a knee joint, a lower leg link portion which extends downward from the side of the knee joint, a torque generator which is disposed on the side of the hip joint, and a damper which is disposed on the side of the knee joint. The torque generator is configured using a cam and a compression spring, generates torque when the affected leg moves rearward due to the forward swinging of the healthy leg, and assists the forward swinging of the affected leg by using the generated torque. Thus, there is no need to provide an actuator such as an electric motor. In addition, the initial compression amount of the compression spring is adjustable. Therefore, the magnitude of generated torque is variable.